Prolonged Detection of PCV2 and Anti-PCV2 Antibody in Oral Fluids Following Experimental Inoculation

Abstract

The onset, level and duration of PCV2 and anti-PCV2 antibody in oral fluid were evaluated using samples collected from experimentally inoculated pigs for 98 days post-inoculation (DPI). Pigs (n = 24) were obtained at 3 weeks of age and randomly allocated to 4 treatment pens of 6 pigs each: (i) negative control group; (ii) inoculated with PCV2a (strain ISU 40895) on DPI 0; (iii) inoculated with PCV2a (strain ISU-40895) on DPI 0 and re-challenged at DPIs 35 and 70; (iv) inoculated with PCV2a (ISU-40895), PCV2b (PVG4072) and PCV2a (ISU-4838) on DPIs 0, 35 and 70, respectively. Serum was collected from each animal, and one oral fluid sample was collected from each pen (group) every other day from DPI 2 through DPI 14 and weekly through 98 DPI. Oral fluid samples were assayed for the presence of PCV2 by quantitative polymerase chain reaction (qPCR) and anti-PCV2 IgG, IgA and IgM antibody isotypes by enzyme-linked immunosorbant assay (ELISA). Serum was assayed for anti-PCV2 IgG by ELISA. Anti-PCV2 antibodies (IgG, IgM and IgA) were detected in oral fluid from experimentally inoculated pigs from DPI 14 with IgG and IgA clearly present at 98 DPI. PCV2 was detected in oral fluid samples from all pens of inoculated pigs at 2 DPI. Thereafter, PCV2 was detected in oral fluid throughout 98 DPI. Overall, the data indicated that PCV2 infection in swine is prolonged, persists in the face of an active antibody response and can be efficiently monitored using oral fluid specimens.

Diagnosis of the Lelystad strain of Porcine reproductive and respiratory syndrome virus infection in individually housed pigs: comparison between serum and oral fluid samples for viral nucleic acid and antibody detection

“…4,17,23,24 The oral fluid collection from individual young piglets showed, however, not to be straightforward and was largely dependent on individual animal behavior. Although the animals were trained to chew on the ropes in 1 week, and oral fluid sampling was conducted before physically manipulating the animals, in the current study, only 2 pigs chewed at every time point, while 2 other pigs would not chew on the ropes throughout the entire experiment.…”

Probability of detecting Porcine reproductive and respiratory syndrome virus infection using pen-based swine oral fluid specimens as a function of within-pen prevalence

“…In contrast, collecting oral fluid specimens requires less labor, is stress free for both animals and human beings, and is a sensitive method for detecting infections in populations. 5,[9][10][11][12] For these reasons, oral fluid sampling has been rapidly adopted by producers and veterinarians and has become routine on many farms. At the Iowa State University Veterinary Diagnostic Laboratory (Ames, IA), the specimen type "swine oral fluid" was entered into the laboratory information management system in February 2010.…”

“…[5][6][7][9][10][11][12] While PCR-based assays are useful for detecting the immediate circulation of pathogens, antibody-based assays are informative regarding herd immunity and the history of an infection in the population. Because both assays reflect different phases of infection, the best test can be selected to serve the need.…”

Detection of African swine fever, classical swine fever, and foot-and-mouth disease viruses in swine oral fluids by multiplex reverse transcription real-time polymerase chain reaction

“…Available from: http://nationalhogfarmer.com/health-diseases/disease-prevention/oral-fluid-collection-enhances-testing-0915). 2,9,[14][15][16][17]19 In 2013, studies reported the experimental detection of FMDV genome or ASF virus (ASFV) antibody in swine OF samples. 13,24 Specifically, OF is defined as the fluid in the oral cavity collected by use of an absorptive device.…”